var obj = {
  _age: 19,
  _eating: () => {
  },
  
  _address: 'bj',
  //使用get、set与defineProperty的区别在于enumerable，get/set为true
  get address() {
    return this._address
  },
  set address(value) {
    this._address = value
  }
}

Object.defineProperties(obj, {
  name: {
    configurable: true,
    enumerable: true,
    writable: true,
    value: 'li',
  },
  age: {
    configurable: false,
    enumerable: false,
    get() {
      return this._age
    },
    set(v) {
      this._age = v
    }
  }
})
console.log(obj)
